Oracle PL/SQL: for i in (select) statement

I am fairly confident with "normal" SQL, but start to get rather more wobbly whenever I go near PL/SQL.

I have a table, called (imaginatively) data_table:

+------------------------------+
| prim_key | field1  | field 2 |
+------------------------------+
| 001      | Hello   | World   |
| 002      | Hello   | Mars    |
| 003      | Goodbye | Mars    |
+------------------------------+

Code (markup):

and I want something like the following output (i.e. row-wise, not col-wise):

Very long descrip of prim_key: 001 
Very long descrip of field 1: Hello 
Very long descrip of field 2: World
 
Very long descrip of prim_key: 002
Very long descrip of field 1: Hello 
Very long descrip of field 2: Mars
 
Very long descrip of prim_key: 003 
Very long descrip of field 1: Goodbye
Very long descrip of field 2: Mars

Code (markup):

Why won't the following work? (Oracle 11g)

for i in ( select prim_key j from data_table ) 
loop 
   select 'Very long descrip of prim_key:', prim_key 
      from data_table where prim_key = i.j ; 
   select 'Very long descrip of field 1:', field1 
      from data_table where prim_key = i.j ; 
   select 'Very long descrip of field 2:', field2 
      from data_table where prim_key = i.j ; 
end loop

Code (markup):

 

The above code should work with small tweaks:a. Use only i in the where clause instead of i.j i.e. from data_table where prim_key = i ;b. Use concatenation - select 'Very long descrip of prim_key:' || prim_key c. Store the result of select statement into a variable, which you may then print.Also, I would suggest that you use only 1 select statement to get the values of all 3 columns (prim_key, field1, field2), instead of 3 separate selects.

 

Thanks. With a combination of your suggestions, plus some of my own ideas, I think I've got this sorted now.